package xq.test;

public class CDnew {
	static int commonDivisor(int a, int b) {
		if (a <= 0 || b <= 0) {
			b = -1;
		} else
			while (a != b) {
				if (a > b)
					a -= b;
				else
					b -= a;
			}
		return b;
	}
}
